The present invention concerns a pile release mechanism for holding pre-installed piles in place on an offshore platform during launching and upending of the platform and for remotely releasing the piles once the offshore platform has been positioned in its final location on the sea floor.
Most offshore platforms, e.g., those used in oil/gas drilling and producing operations, require some form of skirt piles at their bases to add stability to the platform by resisting lateral foundation loads. The installation of such piles requires (1) diver assistance once the offshore platform has been launched, upended, and positioned on the sea floor or (2) an underwater release mechanism when such piles have been pre-installed, i.e., piles attached to the platform before the platform is launched, upended, and positioned on the sea floor.
In the past, two concepts have been generally employed to release pre-installed piling. The first concept is a friction clamp which depends on friction generated by a clamp band to lock the pile to the offshore platform. The variability associated with friction forces and the tension in the clamp band cause reliability of the clamp to be questionable. The second concept consists of connections between the pile and the offshore platform which are shearable by a blow from a hammer. High capacity shear connections are quite variable and may fail prematurely or be difficult to break.
The pile release mechanism of the present invention eliminates the concerns associated with those previous concepts. The mechanism is simple, dependable, and well suited for deep water applications where diver assistance is not desirable.